1. Field of the Invention
The present invention relates to a photometric apparatus of a camera.
2. Related Background Art
A conventional photometric apparatus of a camera has hitherto, as disclosed in Japanese Patent Application Laid-Open No. 2-280581, added outputs of respective photodetectors, judged whether or not the added value is a predetermined value or under and controlled an exposure time in accordance with the judged result.
There arise, however, the following problems inherent in such an apparatus.
An output value of a photometric circuit has to be adjusted so that an output of the photodetector for a principal subject within a field does not come to a photometric lower limit or under and a photometric upper limit or above. In the above-described apparatus, however, the outputs from the photodetectors for a whole picture are added. It may therefore happen that the output of the photodetector for the principal subject does not fall within a range from the photometric lower limit to the photometric upper limit in a state where the principal subject gets darkest as in the case of back light or in a state where the principal subject gets brightest when illuminated with spot light.
Further, if the field contains something to exert an adverse influence on the photometry as done by the sun, and when the outputs of the whole picture are all added, the principal subject comes in an impossible photometry range.
Moreover, if a luminance value of a given in-field area makes an extremely large contribution to a proper exposure value (as in, e.g., main center photometry and spot photometry), and when the outputs of the whole picture are added, the principal subject does not fall within the photometric range in some cases.